idiomatic filter-not or inverting predicate

[Andy C]

Hi,

I was wondering what is the nicest way to do filter-not in Clojure. Here are 3 expressions:

user=> (filter #(apply = %) '([1 2] [1 1]))
([1 1])
user=> (filter #(apply not= %) '([1 2] [1 1]))
([1 2])
user=> (filter #(not (apply = %)) '([1 2] [1 1]))
([1 2])

First one is just a base filtering. Second is taking advantage of having inverted predicate. Now let's assume that we have only a "positive" predicate, hence we would have to invert it by hand. That leads me to 3rd expression above.

I was wondering though is it is possible to somehow get "not" closer to "=", so the fact that we invert it is more obvious ...

Is it possible to do that? Or perhaps there is an easier way to code it up all together ?

Thx,
Andy

[Sam Ritchie]

I think you want complement, like (filter (complement odd?) ...)

Andy C

August 21, 2014 at 2:01 PM

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[Ambrose Bonnaire-Sergeant]

Also see clojure.core/remove.

[Daniel Solano Gómez]

What about 'remove' instead of 'filter'?

Sincerely,

Daniel

[Andy C]

Hi,

Thanks a lot for hints. "remove" was what I needed.

This
    (filter (complement #(apply = %)) '([1 2] [1 1]))

also looks very clean now.

Regards,
Andy